A circuit (C1-C4) is employed in a TWACS transponder (T) installed in an electric meter (M). The transponder generates inbound signals (IB) transmitted from the location of the electric meter to a central location (R). Firmware (F) within the transponder controls the flow of current for each pulse through the circuit by triggering a semi-conductor device such as a SCR (X1) or TRIAC (X2). The resulting current flow through the inductor for a subsequent pulse, regardless of the pulse's polarity, will be in the opposite direction to that of the previous pulse. The result is to maintain a constant level of magnetization of the inductor core which does not have to be overcome by energy in the subsequent pulse resulting in amplitude of all the pulses imposed on an AC waveform being substantially the same.
A method of detecting a signal transmitted over one phase of a multi-phase power distribution system, components of the signal concurrently appearing on all phases of the system. The method includes detecting the components of each signal appearing on each phase, including neutral, of the system. Detected signals are provided to a signal processor which processes them to produce a detected signal which is a composite of all the components. The signals are combined by a weighted summation scheme that takes into account signal and noise correlation properties to simultaneously maximize signal strength and suppress noise. If other signals are present on other phases of the system, any resulting interference is canceled out from the detected signal to further improve the quality of the detected signal.
A meter (M) installed by a utility at a customer site to measure the usage of a commodity supplied by the utility to the customer comprises an enclosure (E) in which is installed measuring apparatus (A) for measuring the amount of usage of the commodity by the customer at any one time. A web server (S) provides information obtained from the measuring apparatus and the utility to the customer. A wireless connection (C) between the web server and a customer device (D) allows the information and utility provided information to be displayed to the customer as well as enabling the device to obtain information from the meter so to determine when, and for how long, the device can be most cost efficiently operated.
A transmitter transmits an outbound message signal via the power distribution system. The transmitter includes a spreader for spreading the spectrum of the communications signal before transmitting the outbound message signal. A receiver despreads the spectrum of the received digitized signal and digitally demodulates the received despread signal to generate the message. The transmitted signal is orthogonal to a source of interference on the power distribution system.
When load control is activated by a local or remote mechanism to control a load, the method and system use a usage profile of the load and one or more of (1) interval start times, (2) ON/OFF or OFF/ON cycling and (3) predefined periods during which load must not be allowed to run (e.g., dead zones) to determine when a particular piece of equipment is allowed to shed or run thereby reducing the probability of occurrence of cyclical and non-cyclical aggregate peaking of usage wherein cyclical peaking is manifested as an artifact of the local load control rules during a load control event.
An agile switched-load transmitter for a communications system for a power distribution network comprises a resonant transponder (T1) with a variable primary frequency. The transmitter significantly increases the bandwidth for communications, significantly lessens the effect of bandwidth noise, and greatly improves both the quality of communications and data throughput. Switches (S1, S2) selectively connect the transponder to the communications systems and control current flow through a resonant circuit of the unit, particularly the timing between charging and discharging of a capacitive component thereof. This allows the frequency of operation of the transmitter to be controlled so an inbound signal has a frequency within a range of selected frequencies, rather than a fixed frequency, and enables the transponder to deliver an output signal of relatively high power that propagates through the power distribution network with relatively little loss in signal strength.
A receiver and method for a transponder of a two-way automatic communications system (TWACS) used by an electrical utility in which analog outbound messages are sent from the utility to a consumer and inbound, reply messages are sent from the consumer to the utility. The receiver and method enable a transponder to detect the outbound messages and include A/D conversion and digital processing for demodulating a digitized signal and providing the outbound message.
A switched-load, resonant transmitter (T2) for inbound signaling in a two-way automatic communications system (TWACS). The load is purely reactive containing both inductive (L) and capacitive (C) elements. When connected in a power transmission network, the transmitter generates signals useful for passband communications. The transmitter consumes, on average, 100 times less power than resistive switched-load transmitters currently in use in TWACS networks. Signal strength is comparable to that produced by the transmitters currently in use at frequencies near 1kHz, but is very low otherwise.
Detection of fault occurrences within a power distribution system. A transient detector and fault classification system (10) implements an algorithm that detects transients which may result from the occurrence of a fault in the power distribution system. The system includes a detection module (18) which processes a set samples obtained from electrical waveforms propagated of through the power distribution system and appear to be statistically anomalous compared to other sample data. This is done using an adaptive detection algorithm that is applied when large changes occur in a waveform over a relatively short period of time. The identified samples are then provided to a signal classifier module (20) which processes sets of samples to classify a transient they represent as a likely fault occurrence or some other type of anomaly which is likely not a fault occurrence. If a transient is classified as representing a likely fault occurrence, a polling module (30) polls users of the distribution system to determine if a fault has occurred within the distribution system, and, if so, where.
Detection of fault occurrences within a power distribution system. A transient detector and fault classification system (10) implements an algorithm that detects transients which may result from the occurrence of a fault in the power distribution system. The system includes a detection module (18) which processes a set samples obtained from electrical waveforms propagated of through the power distribution system and appear to be statistically anomalous compared to other sample data. This is done using an adaptive detection algorithm that is applied when large changes occur in a waveform over a relatively short period of time. The identified samples are then provided to a signal classifier module (20) which processes sets of samples to classify a transient they represent as a likely fault occurrence or some other type of anomaly which is likely not a fault occurrence. If a transient is classified as representing a likely fault occurrence, a polling module (30) polls users of the distribution system to determine if a fault has occurred within the distribution system, and, if so, where.
A point-to-point communications system (20) for transmitting messages from any location (A) within a power distribution system or network (10) to any other location (B) within the network. A transceiver (12) at the one location includes a transmitter (X) that impresses a waveform (WR) on a waveform (WG) propagated by the network to supply power throughout the network. The transmitter is a resonant transmitter that includes a reactive load (13) which is selectively connected to and disconnected from the power distribution network. A controller (16) controls operation of the transmitter to connect and disconnect the reactive load from the network so to impress on the propagated waveform a dampened sinusoidal waveform whose characteristics represent information conveyed over the power distribution system. A receiver (Yn) at the other location receives and demodulates the dampened sinusoidal waveform to extract therefrom the information being conveyed by it.
A point-to-point communications system (20) for transmitting messages from any location (A) within a power distribution system or network (10) to any other location (B) within the network. A transceiver (12) at the one location includes a transmitter (X) that impresses a waveform (WR) on a waveform (WG) propagated by the network to supply power throughout the network. The transmitter is a resonant transmitter that includes a reactive load (13) which is selectively connected to and disconnected from the power distribution network. A controller (16) controls operation of the transmitter to connect and disconnect the reactive load from the network so to impress on the propagated waveform a dampened sinusoidal waveform whose characteristics represent information conveyed over the power distribution system. A receiver (Yn) at the other location receives and demodulates the dampened sinusoidal waveform to extract therefrom the information being conveyed by it.
A method for use in a power line communication systems for an electrical distribution system (1) to quickly and accurately poll electrical meters (6) installed at user facilities to determine if an outage has occurred at a facility. An outbound communications message is transmitted to the meter at the facility requesting a short response consisting of a bit pattern that is either partially or completely known to the receiver. Any perceived response from the meter is then processed to ascertain whether or not the meter actually transmitted a message. Receipt of a message indicates that an outage has not occurred at that site, while an indication the message was not received indicates an outage has likely occurred. In processing the received message, two types of errors can potentially occur; i.e., a false positive or a false negative.
G08B 9/00 - Order telegraph apparatus, i.e. means for transmitting one of a finite number of different orders at the discretion of the user, e.g. bridge to engine room orders in ships
G08B 25/00 - Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems
G08B 1/08 - Systems for signalling characterised solely by the form of transmission of the signal using electric transmission
G08B 23/00 - Alarms responsive to unspecified undesired or abnormal conditions
A demand response unit (DRU) interposed between a utility's electrical power line (PL) and at least one load (L1-Ln) to which power is supplied by the utility over the line. A detector (Fdet or Vdet) measures a characteristic (frequency F, voltage V) of an electrical waveform (W) by which power is transmitted by the utility to the load. The detector (Fdet or Vdet) determines both when the measured frequency (F) or voltage (V) exceeds a predetermined threshold for a first predetermined period of time; and, if the threshold is exceeded, when the frequency (F) or voltage (V) exceeds the second predetermined threshold for a second predetermined period of time. For this purpose, the detector (Fdet or Vdet) processes a predetermined number of intervals of the waveform and produces an average value of the characteristic which is compared to the threshold. This is done to reduce the effect of extraneous events which may temporarily change the value of the frequency or voltage. A power control (PC) is responsive to an output from the detector to, at least, partially interrupt flow of power to the load during the period of time when the measured frequency or voltage exceeds the threshold, thereby to reduce the load on the utility.
H02J 3/12 - Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
G01R 19/02 - Measuring effective values, i.e. root-mean-square values
G01R 23/00 - Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
15.
UNDER FREQUENCY/UNDER VOLTAGE DETECTION IN A DEMAND RESPONSE UNIT
A demand response unit (DRU) interposed between a utility's electrical power line (PL) and at least one load (L1-Ln) to which power is supplied by the utility over the line. A detector (Fdet or Vdet) measures a characteristic (frequency F, voltage V) of an electrical waveform (W) by which power is transmitted by the utility to the load. The detector (Fdet or Vdet) determines both when the measured frequency (F) or voltage (V) exceeds a predetermined threshold for a first predetermined period of time; and, if the threshold is exceeded, when the frequency (F) or voltage (V) exceeds the second predetermined threshold for a second predetermined period of time. For this purpose, the detector (Fdet or Vdet) processes a predetermined number of intervals of the waveform and produces an average value of the characteristic which is compared to the threshold. This is done to reduce the effect of extraneous events which may temporarily change the value of the frequency or voltage. A power control (PC) is responsive to an output from the detector to, at least, partially interrupt flow of power to the load during the period of time when the measured frequency or voltage exceeds the threshold, thereby to reduce the load on the utility.
H02J 3/12 - Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
G01R 19/02 - Measuring effective values, i.e. root-mean-square values
G01R 23/00 - Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
16.
WIRELESS BROADBAND COMMUNICATIONS NETWORK FOR A UTILITY
A communications network (12) for use by a utility (10) for communication, command, and control of the utility's distribution area for gas, water and electrical services including the utility's distribution system, security, workforce, and asset management. The network includes apparatus for obtaining information and data concerning usage of the electricity, gas, or water by each of the utility's customers, the operation of installations throughout the system, and how electricity, gas, or water is being distributed throughout the system. The information and data from each source (16) is processed to provide an up-to-date overview of the system and its operation to the utility's management and operating personnel. This includes identification of any current problems, including distribution or security, within the system, and asset monitoring and management to identify possible future problems which may occur within a predetermined period of time. Reports generated as a result of processing the information and data, besides providing current status information, also provide management and operating personnel with information as to ways of alleviating any current problems identified within the system, and steps which can be taken to forestall possible future problems which are identified.
A communications network (12) for use by a utility (10) for communication, command, and control of the utility's distribution area for gas, water and electrical services including the utility's distribution system, security, workforce, and asset management. The network includes apparatus for obtaining information and data concerning usage of the electricity, gas, or water by each of the utility's customers, the operation of installations throughout the system, and how electricity, gas, or water is being distributed throughout the system. The information and data from each source (16) is processed to provide an up-to-date overview of the system and its operation to the utility's management and operating personnel. This includes identification of any current problems, including distribution or security, within the system, and asset monitoring and management to identify possible future problems which may occur within a predetermined period of time. Reports generated as a result of processing the information and data, besides providing current status information, also provide management and operating personnel with information as to ways of alleviating any current problems identified within the system, and steps which can be taken to forestall possible future problems which are identified.
A method for load control in an electrical distribution system using energy usage profiles based on temporal measurements. A load control unit (10) installed at a customer site profiles equipment (E1-En) directly connected to the load control unit and remotely located equipment (RE1-REn) wirelessly connected to the load control unit using measurements of time rather than energy usage. This reduces the cost and complexity of the load control unit. Profiling is done for individual pieces of load controlled equipment rather than for the site as a whole. This improves data resolution. The load control unit controls the load only when the equipment is powered, and adaptively synchronizes load shedding during this time, so to improve local load control performance. Termination of a load control event results in gradual reduction in load shedding so to control the inrush of demand seen by the distribution system. Performance metrics related to the load control are provided to the utility such that complexity of the system is reduced through decreased computations.
H02J 3/14 - Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by switching loads on to, or off from, network, e.g. progressively balanced loading
H02J 13/00 - Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
19.
A METHOD FOR LOAD CONTROL USING TEMPORAL MEASUREMENTS OF ENERGY FOR INDIVIDUAL PIECES OF EQUIPMENT
A method for load control in an electrical distribution system using energy usage profiles based on temporal measurements. A load control unit (10) installed at a customer site profiles equipment (E1-En) directly connected to the load control unit and remotely located equipment (RE1-REn) wirelessly connected to the load control unit using measurements of time rather than energy usage. This reduces the cost and complexity of the load control unit. Profiling is done for individual pieces of load controlled equipment rather than for the site as a whole. This improves data resolution. The load control unit controls the load only when the equipment is powered, and adaptively synchronizes load shedding during this time, so to improve local load control performance. Termination of a load control event results in gradual reduction in load shedding so to control the inrush of demand seen by the distribution system. Performance metrics related to the load control are provided to the utility such that complexity of the system is reduced through decreased computations.
H02J 3/14 - Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by switching loads on to, or off from, network, e.g. progressively balanced loading
20.
A GENERAL METHOD FOR LOW-FREQUENCY DATA TRANSMISSION ON A POWER LINE
A method for producing a set of inbound pulse patterns and detection vectors for lengths longer than 4 cycles in an AC waveform. These are used for generating inbound messages in a two-way automatic communication system (TWACS). The method uses Hadamard matrices adapted to generate a set of detection vectors by permuting rows of a matrix and removing certain columns of the matrix to meet system design requirements. The method can be extended to any length and modified to accommodate multiple pulses per half-cycle to support higher data rates.
A method of data compression for use in a data communication's system for an electrical utility or the like to affect the most efficient transfer of data. The data is first formed into a forming a block (B). A parameter (M) is selected from among a group of parameters. Each data value in the block is divided by the selected parameter to produce, for each data value, a quotient (q = L n / M ˩) and a remainder (r = n - qM). The quotient of each data value is encoded using unary coding in which the value for the quotient is encoded by transmitting an appropriate number of zeroes followed by a one. The remainder of each data value is encoded using binary encoding, and the resultant encoded block of data is then transmitted. The data values comprising the block of data are positive integer values and the encoding employs a Golomb-Rice code defined by a positive integer parameter.
A method of Demand Response (DR) utilizing a Load Control Transponder (LCT) installed at the location of an electricity consumer. A DR program, in conjunction with the LCT, allows a consumer to determine, in advance, when they will reduce their demand on an electricity supply system. The consumer is informed of price points at which the cost of energy increases due to overall demand. The consumer then determines if, and when, they will reduce their demand on the system when a price point is reached. In addition, when an unplanned, critical event occurs, the method enables the utility to bypass any intermediate consumer established settings and immediately and directly drop the level of energy consumption to the consumer's lowest selected level for continuing service thereby to shed sufficient load on the system to maintain an adequate level of electricity supply. Once the event has been resolved, the method enables the utility to restore the consumer's previous level of usage.
G01R 21/00 - Arrangements for measuring electric power or power factor
H02J 13/00 - Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
G01R 21/133 - Arrangements for measuring electric power or power factor by using digital technique
23.
METHOD OF CORRECTING MESSAGE ERRORS USING CYCLIC REDUNDANCY CHECKS
A method of correcting errors in a message transmitted over a digital communication channel, where the message was encoded using a CRC for purposes of error detection. A parity-check matrix representation of the CRC is computed for any fixed-length message, and that parity-check matrix is combined with the parity-check matrix for any error correcting code that used in conjunction with the CRC. The combined parity-check matrix is extended using sparsification algorithms to allow it to work well under a message passing decoder (MPD). Received messages are decoded using the message passing decoder, making it possible to correct more errors than if the CRC were decoded in a conventional manner.
H04L 1/00 - Arrangements for detecting or preventing errors in the information received
H03M 13/05 - Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words using block codes, i.e. a predetermined number of check bits joined to a predetermined number of information bits
A method for use in a power line communication systems for an electrical distribution system (1) to quickly and accurately poll electrical meters (6) installed at user facilities to determine if an outage has occurred at a facility. An outbound communications message is transmitted to the meter at the facility requesting a short response consisting of a bit pattern that is either partially or completely known to the receiver. Any perceived response from the meter is then processed to ascertain whether or not the meter actually transmitted a message. Receipt of a message indicates that an outage has not occurred at that site, while an indication the message was not received indicates an outage has likely occurred. In processing the received message, two types of errors can potentially occur; i.e., a false positive or a false negative.
H02J 13/00 - Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
H04B 3/54 - Systems for transmission via power distribution lines
A quick response system incorporated in a TWACS for mapping an outage in an electrical distribution system with-out having to continuously poll the electrical meters connected to the system. In a primary embodiment of the invention when a fault is sensed to have occurred, the amplitude of the fault is measured to determine if the fault is a medium voltage fault, or a low voltage fault. The pattern of the fault signature and change in load, both before and after the fault, are examined to determine what protective device was triggered by the fault. Using this information, and knowledge of the number and location of electrical meters connected in the distribution system, a population of meters to be polled is determined. By polling the identified population, a map of the extent of the outage is readily determined, and the time to respond to the fault and restore service is reduced.
Tamper detection apparatus for an electric meter (M) installed at a facility supplied power through an electrical distribution system, the meter being connected to the facility using a receptacle (K) and monitoring electricity usage at the facility for electricity delivered to the facility flowing through the meter. A sensor (RR) senses movement of the meter more than a predetermined amount with respect to the receptacle, whether or not electricity is flowing through the meter, and produces a tampering signal when this occurs. A second and optional sensor (Z) senses the proximity of the meter to its receptacle with removal of meter from its receptacle producing a tampering signal representative thereof. Generation of a tampering signal results in a tamper alert signal being transmitted to the system through a two-way communications path established between the facility and the system.
patents
